1. Field of the Invention
The present invention relates to rotary tillers, and in particular, the present invention relates to rotary tillers adapted for tilling between plants planted in a row and other crops difficult to till with conventional drag-type tillers.
2. Description of the Prior Art
Elimination of plants, such as weeds, between and among row crops has been a major problem in agriculture. Typically, for row crops, a drag-type tiller has been used to till the soil and expose the roots of the weeds. However, when the crops in the rows get too high, tillage by drag-type tillers becomes impossible since the frame of the tiller holding the tilling blades will damage the plants. This is particularly true of perennial crops, such as small trees in a nursery, grapevines and various nursery shrubs.
One alternative for tilling such row crops would be manual hoeing. This, however, greatly increases labor costs for maintaining such crops.
There have been various other attempts in the prior art to overcome the problem of tilling the soil between and among row crops. A number of tilling machines having rotary tillers have been devised for mounting on vehicles, such as tractors. The Bezzerides et al U.S. Pat. No. 3,401,753, the Giusti et al U.S. Pat. No. 3,419,086 and the van der Lely U.S. Pat. Nos. 4,043,401 and 4,224,998 show rotary tiller devices which are dragged between rows behind a tractor. The Giusti et al patent further shows a cultivator which is fitted onto a three-point hitch and is movable in an upward and downward direction. However, none of the tiller devices in the immediately above-mentioned patents are capable of tilling the soil between the plants in any one particular row.
The Parks et al U.S. Pat. No. 4,332,299 and the Schenk et al U.S. Pat. No. 4,342,366 show rotary cultivators which are movable in a vertical direction from a non-tilling position to a tilling position. Moving the tiller in a vertical direction from a tilling to a non-tilling position avoids damaging plants when tilling between the plants in a particular row. However, with the above devices the soil between the rows must then be tilled in a separate operation.
The Caggiano, Jr. U.S. Pat. No. 3,117,632 shows a cultivator having a rotary tiller device supported on a frame at a distal end which telescopes in and out among the rows. The device of the Caggiano, Jr. patent includes a highly complicated hydraulic piston arrangement which moves the rotary tiller device in and out of a row of plants.
The Anderson U.S. Pat. No. 4,287,955 is directed to a rotary tiller that pivots about an axis in an upward and downward direction in one embodiment and in another embodiment the rotary tiller is permitted to swivel in a horizontal direction. The tilling apparatus of the Anderson patent does not provide for good control of the tiller in and among the rows and is not suitable for mounting on the side of today's modern tractors.
A commercially available tiller is sold under the trademark "Weed Badger" by Town & Country Research & Development, Inc. of Marion, N.D. The "Weed Badger" tiller is mounted on the end of a support frame having a first member pivotally attached to a bracket on a tractor and a second member pivotally attached to a distal end of the first member. Both members pivot about horizontal axes. The members are moved by a pair of hydraulic cylinders that are synchronized through a common valve which results in a perpendicular movement of the tiller head in and out of the row that is being tilled. The "Weed Badger" tiller also uses a complicated hydraulic scheme in moving the support frame in and out of rows that requires extra cooling capacity in the tractor.